Incandescent electric lamp.



PATENTED DEC. 18, 1906.

G. A. NBLLIS. INGANDESCENT ELECTRIC LAMP.

APPLICATION FILED SBPT.Z5,1905.

UNITED sTArEs PATENT OFFICE- GEORGE A. NELLIS, OF ALLEGHENY, PENNSYLVANIA. I

INCANDESCENT ELECTRIC LAMP- Specification. of Letters Patent,

Patented Dec. 18, 1906.

To all whom it may concern.-

Be it known that I, GEoRGE A. NELLIS, a citizen of the United States, residing at Allegheny, in the county of Allegheny and State of Pennsylvania, have invented certain new and. useful Improvements in Incandescent Electric Lamps, of which the following is a specification;

M invention relates to incandescent electric amps and analogous devices, which depend for their successful operation upon the employment of a vacuum chamber in connection with wires leading therein, and more particularly to the mount for the wires and the seal at the point where the wires pass into the chamber. 7,

The objects of my invention are, to provide an improved form of seal which will per mit of the use of leading-in wires composed of copper or other metals, such as iron, nickel, silver, steel or composition of. metals, in connection with a mount composed of a nonconducting material having a different coefficient of expansion, such as glass, porcelain or other vitreous substances. To provide a seal and mount in which the leading-in wires will be effectually se arated and anchored, whereby all danger 0 short circuiting will be avoided and the wires protected from any damage that might occur during subsequent handling, and to provide a device in which the cost of production is greatly reduced by reason of the substitution of leadingin wires composed of cop er or other metals, for those composed wholl y or in part of platinum. These objects and other advantages which will hereinafter a ear, I attain by means of the construction iil iistrated in preferred form in the accompanying drawings, wherein- Figure 1, is a longitudinal central section of an incandescent electric lamp globe having my improved mount and seal applied thereto;

Figure 2, is a cross-section of the same, on the line (2) of Figure 1, looking toward the mount, and I Figure 3, is a detail view, on an enlarged scale of a portion of one of the leading-in wires, at the point where it is sealed in the mount.

Heretofore it has been found impractical toproduce a perfect seal around leading-in wires, when such wires are composed of other metals than platinum, by reason of the great difference in the coeflicient of expansion between the wires and the glass mount or seal and the fact that such wires as copper, iron etc., oxidize easily when subjected to the ac tion of heat, when being embedded in the glass. The contraction of the glass on cooling and oxidization of the wires consequent upon the sealing operation being sufficient to cause an imperfect seal.

I have discovered, however, that by the use of a certain form of leading-in wire in connection with a mount or stem of a suitable form, and further by using a vitreous cement of a sufiiciently low fusing point as not to burn or oxidize the wires, a perfect seal may be obtained. Any suitable cement may be used for this purpose, such as glazes, enamels or fluxes composed of oxids of lead and tin, silica and borax in proper roportions, the only requisite being that said cements should preferably fuse at a temperature between 300 and 600 degrees.

In the accomplishment of these objects I may employ a lamp bulb 4, of the usual construction and which may be of any preferred design, together with a mount or stem 5, composed of glass, porcelain, or other vitreous material. The leading-in wires 6 enter through openings 7, located in the lower end of the mount and are sealed therein in a manner to be presently described.

In order to compensate for the unequal expansion and contraction of the mount and wires and protect the latter as against oxidization during the sealing process, whereby a perfect seal is insured between the wire and the mount, the openings 7 are tapered toward their outer ends and terminate in a groove or depression 8, and the wires 6 are roughened and helically wound or convoluted for a portion of their length, where they ass through the openings 7, as illustrate in Figs. 1 and 3. The openings and groove will permit of the use of a sufficient quantity of the low fusing cement to fully protect the wires against oxidization. The shape of said openings and groove will cause the cement to settle closely around the wires, particularly at the point where they emerge rom the mount and by reason of the interstices caused by the roughening of the wires and the greater amount of surface within the openings 7, due to the helix or convolution, a perfect seal will be insured. Furthermore y reason of the helix or convolution the direction of the line of expansion and contraction of the wires will be such that the completeness of the seal will in no wise be interfered with.

.ofa like character, such for instance as those known as oxychloride or oxyphosphate cements, may be used if desired.

By thus forming the wire in a helical or convoluted form I allow for the necessary expansion and eontnaction without loosening the seal,'which will permit of the use of a cheaper wire than platinum. Other advantages of the device will readily occur to those familiar with the art.

Having thus described my invention and illustrated its use, what I claim as new, and desire to secure by Letters Patent, is the fol lowing:

1. An incandescent electric lamp, having a -leading-in wire, a section or portion of which within-the seal is helically wound.

2. An incandescent electric lamp, having a leading-in wire, a portion of which is roughened and convoluted, said portion being .sealed within the mount.

3. An incandescent electric lamp mount or. stem, comprising a low fusing cement seal and a non-conducting protective seal for the leading-in wires, said wires being convoluted within the seal.

4. An incandescent electric lamp moun-t or stem, comprising a body portion provided with openings for the admission of the lead,- ing-in wires, and a transversely disposed groove connecting said openings at one end.

5. An incandescent electric lamp mount or stem, comprising a body portion provided with openings for the admission of the leading-in wires, and a transversely disposed groove connecting the openings at their outer ends, said outer ends of the openings-being of a smaller diameter than theinner ends.

6.- An incandescent electric lamp mount or stem, comprising a hollow body portion provided with openings for the admission of the leading-inwires, a transversely disposed groove connecting said openings at their outer ends, together with a low fusing cement contained insaid openings and groove, and a non-conducting cement within the body por tion, for sealing the wires within the mount.

In testimony whereof I have hereunto signed my name in the presence of the two subscribed witnesses.

GEORGE A. NELLIS.

Witnesses:

F. E. GAITHER, HARVEY L. LECHNER. 

